1. Field of the Invention
This invention relates in general to mobile phone networks, and more specifically, to predictive wakeup for push-to-talk-over-cellular (PoC) call setup optimizations in a mobile phone network.
2. Description of Related Art
Advanced voice services (AVS), also known as Advanced Group Services (AGS), such as two-way half-duplex voice calls within a group, also known as Push-to-Talk-over-Cellular (PoC), Push-to-Talk (PTT), or Press-to-Talk (P2T), as well as other AVS functions, such as Push-to-Conference (P2C) or Instant Conferencing, Push-to-Message (P2M), etc., are described in the co-pending and commonly-assigned patent applications cross-referenced above and incorporated by reference herein. These AVS functions have enormous revenue earnings potential for wireless communications systems, such as cellular networks and personal communications systems (PCS) networks.
Currently, there are two major approaches employed in providing advanced voice services in wireless communications systems. One approach is based on circuit-switched technology, wherein voice circuits are reserved during the entire duration of an AVS or PoC call. Circuit-switched PoC is deployed by many operators around the world with technologies such as NEXTEL's iDEN and Kodiak Network's RTX.
Another approach to PoC is based on packet or voice-over-IP (VoIP) technologies. This approach capitalizes on the “bursty” nature of PoC conversations and makes network resources available only during talk bursts and hence is highly efficient from the point of view of network and spectral resources. This approach promises compliance with newer and emerging packet-based standards, such as GPRS (General Packet Radio Service), UMTS (Universal Mobile Telecommunications System), 3G, 4G, LTE, etc.
In either approach, an effective PoC implementation requires PoC session setup times of less than 2 seconds for acceptable performance. In practice, these setup times are difficult to achieve in view of inherent network parameters. For example, to conserve handset battery life, networks are tuned such that handset terminals are put in battery conserving sleep mode and will “wakeup” periodically to listen to the paging channel. This results in inherent delays of longer than 2 seconds in setting up of PoC sessions, which is unacceptably long.
Thus, there is a need in the art for improvements to the methods and systems for delivering the advanced voice services, such as PoC, that comply with both existing circuit-based networks and emerging wireless packet-based standards and yet provide superior user experiences by reducing PoC call setup times to within acceptable limits. The present invention satisfies this need.